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refactors/cleanups
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@iaik-jheher
iaik-jheher committed Dec 6, 2024
1 parent b650d38 commit 8c26b6a
Showing 1 changed file with 39 additions and 62 deletions.
101 changes: 39 additions & 62 deletions indispensable/src/commonMain/kotlin/at/asitplus/signum/indispensable/CryptoPrivateKey.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -102,24 +102,28 @@ sealed class CryptoPrivateKey(

/**
* PKCS#1 RSA Private key representation as per [RFC 8017](https://datatracker.ietf.org/doc/html/rfc8017/#appendix-A.1.2) augmented with optional [attributes].
* Attributes are never SEC-1 encoded, but are relevant when PKCS#8-encoding a private key.
*
* Attributes are never PKCS#1 encoded, but are relevant when PKCS#8-encoding a private key.
*/
class RSA
/** @throws IllegalArgumentException in case invalid parameters are provided*/
@Throws(IllegalArgumentException::class)
constructor(
/**
* The [CryptoPublicKey.RSA] matching this private key
*/
/** The [CryptoPublicKey.RSA] (n,e) matching this private key */
override val publicKey: CryptoPublicKey.RSA,
val d: BigInteger,
val p: BigInteger,
val q: BigInteger,
val dp: BigInteger,
val dq: BigInteger,
val qi: BigInteger,
val otherPrimeInfos: List<OtherPrimeInfo>?,
/** d: the private key such that d*e = 1 mod phi(n) */
val privateKey: BigInteger,
/** p: the first prime factor */
val prime1: BigInteger,
/** q: the second prime factor */
val prime2: BigInteger,
/** dP: the first factor's CRT exponent */
val prime1exponent: BigInteger,
/** dQ: the second factor's CRT exponent */
val prime2exponent: BigInteger,
/** qInv: the factors' CRT coefficient (q^(-1) mod p) */
val crtCoefficient: BigInteger,
/** information about additional prime factors: triples (r_i, d_i, t_i) of prime factor, exponent, coefficient */
val otherPrimeInfos: List<PrimeInfo>?,
attributes: List<Asn1Element>? = null
) : CryptoPrivateKey(attributes), WithPublicKey<CryptoPublicKey.RSA> {

Expand All @@ -135,29 +139,23 @@ sealed class CryptoPrivateKey(
init {
val n = publicKey.n.toBigInteger()
val e = publicKey.e.toBigInteger()
// the coefficients are intentionally swapped; see RFC 8017 sec 3.2 note 1
val primeInfos1 = OtherPrimeInfo(prime = q, exponent = dq, coefficient = BigInteger.ONE)
val primeInfos2 = OtherPrimeInfo(prime = p, exponent = dp, coefficient = qi)
// the primes and exponents are intentionally swapped; see RFC 8017 sec 3.2 note 1
val primeInfo1 = PrimeInfo(prime = prime2, exponent = prime2exponent, coefficient = BigInteger.ONE)
val primeInfo2 = PrimeInfo(prime = prime1, exponent = prime1exponent, coefficient = crtCoefficient)

var product = BigInteger.ONE
(sequenceOf(primeInfos1, primeInfos2) + (otherPrimeInfos?.asSequence() ?: sequenceOf()))
(sequenceOf(primeInfo1, primeInfo2) + (otherPrimeInfos?.asSequence() ?: sequenceOf()))
.forEachIndexed { i, info ->
val pminusone = info.prime - BigInteger.ONE
require(product.times(info.coefficient).mod(info.prime) == BigInteger.ONE)
{ "t_$i != (r_0 * ... * r_${i-1})^(-1) mod r_$i" }
product *= info.prime
require(info.exponent == d.mod(pminusone)) { "d_$i != d mod (p_$i - 1)" }
require(info.exponent == privateKey.mod(pminusone)) { "d_$i != d mod (p_$i - 1)" }
require(e.multiply(info.exponent).mod(pminusone) == BigInteger.ONE)
}
require(product == n) { "p1 * p2 * … * pk != n" }
}

private fun BigInteger.lcm(other: BigInteger): BigInteger {
val mul = this * other
val gcd = this.gcd(other)
return mul / gcd
}

/** Encodes this private key into a PKCS#1-encoded private key */
val asPKCS1 = object : PemEncodable<Asn1Sequence> {
override val canonicalPEMBoundary get() = EB_STRINGS.RSA_PRIVATE_KEY_PKCS1
Expand All @@ -183,12 +181,12 @@ sealed class CryptoPrivateKey(
if (otherPrimeInfos != null) +Asn1.Int(1) else +Asn1.Int(0)
+publicKey.n
+publicKey.e
+Asn1.Int(d)
+Asn1.Int(p)
+Asn1.Int(q)
+Asn1.Int(dp)
+Asn1.Int(dq)
+Asn1.Int(qi)
+Asn1.Int(privateKey)
+Asn1.Int(prime1)
+Asn1.Int(prime2)
+Asn1.Int(prime1exponent)
+Asn1.Int(prime2exponent)
+Asn1.Int(crtCoefficient)
otherPrimeInfos?.let {
+Asn1.Sequence {
it.forEach { info -> +info }
Expand All @@ -209,7 +207,7 @@ sealed class CryptoPrivateKey(
* }
* ```
*/
class OtherPrimeInfo(
class PrimeInfo(
val prime: BigInteger,
val exponent: BigInteger,
val coefficient: BigInteger,
Expand All @@ -226,7 +224,7 @@ sealed class CryptoPrivateKey(

override fun equals(other: Any?): Boolean {
if (this === other) return true
if (other !is OtherPrimeInfo) return false
if (other !is PrimeInfo) return false

if (prime != other.prime) return false
if (exponent != other.exponent) return false
Expand All @@ -242,15 +240,15 @@ sealed class CryptoPrivateKey(
return result
}

companion object : Asn1Decodable<Asn1Sequence, OtherPrimeInfo> {
companion object : Asn1Decodable<Asn1Sequence, PrimeInfo> {

@Throws(Asn1Exception::class)
override fun doDecode(src: Asn1Sequence): OtherPrimeInfo = runRethrowing {
override fun doDecode(src: Asn1Sequence): PrimeInfo = runRethrowing {
val prime = src.nextChild().asPrimitive().decodeToBigInteger()
val exponent = src.nextChild().asPrimitive().decodeToBigInteger()
val coefficient = src.nextChild().asPrimitive().decodeToBigInteger()
require(src.hasMoreChildren() == false) { "Superfluous Data in OtherPrimeInfos" }
OtherPrimeInfo(prime, exponent, coefficient)
PrimeInfo(prime, exponent, coefficient)
}

}
Expand All @@ -270,9 +268,7 @@ sealed class CryptoPrivateKey(
@Throws(Asn1Exception::class)
override fun doDecode(src: Asn1Sequence): RSA = doDecode(src, null)

/**
* PKCS1 decoding of an ASN.1 private key, optionally supporting attributes for later PKCS#8 encoding
*/
/** PKCS1 decoding of an ASN.1 private key, optionally supporting attributes for later PKCS#8 encoding */
@Throws(Asn1Exception::class)
fun doDecode(src: Asn1Sequence, attributes: List<Asn1Element>? = null): RSA = runRethrowing {
val version = src.nextChild().asPrimitive().decodeToInt()
Expand All @@ -286,9 +282,9 @@ sealed class CryptoPrivateKey(
val exponent2 = src.nextChild().asPrimitive().decodeToBigInteger()
val coefficient = src.nextChild().asPrimitive().decodeToBigInteger()

val otherPrimeInfos: List<OtherPrimeInfo>? = if (src.hasMoreChildren()) {
val otherPrimeInfos: List<PrimeInfo>? = if (src.hasMoreChildren()) {
require(version == 1) { "OtherPrimeInfos is present. RSA private key version must be 1" }
src.nextChild().asSequence().children.map { OtherPrimeInfo.decodeFromTlv(it.asSequence()) }
src.nextChild().asSequence().children.map { PrimeInfo.decodeFromTlv(it.asSequence()) }
} else {
require(version == 0) { "OtherPrimeInfos is not present. RSA private key version must be 0" }
null
Expand All @@ -313,7 +309,7 @@ sealed class CryptoPrivateKey(

/**
* SEC1 Elliptic Curve Private Key Structure as per [RFC 5915](https://datatracker.ietf.org/doc/html/rfc5915) augmented with optional [attributes].
* Attributes are never SEC-1 encoded, but are relevant when PKCS#8-encoding a private key.
* Attributes are never SEC1 encoded, but are relevant when PKCS#8-encoding a private key.
*/
sealed class EC(
val privateKey: BigInteger,
Expand Down Expand Up @@ -487,11 +483,6 @@ sealed class CryptoPrivateKey(
require(version == 1) { "EC public key version must be 1" }
val privateKeyOctets = src.nextChild().asOctetString().content

fun Asn1ExplicitlyTagged.decodeECParams(): ObjectIdentifier {

return ObjectIdentifier.decodeFromTlv(nextChild().asPrimitive())
}

var curve: ECCurve? = null
var publicKey: Asn1BitString? = null
while (src.hasMoreChildren()) {
Expand Down Expand Up @@ -539,23 +530,21 @@ sealed class CryptoPrivateKey(
fun fromIosEncoded(keyBytes: ByteArray): KmmResult<CryptoPrivateKey.WithPublicKey<*>> = catching {
if (keyBytes.first() == ANSIECPrefix.UNCOMPRESSED.prefixByte) CryptoPrivateKey.EC.iosDecodeInternal((keyBytes))
else CryptoPrivateKey.RSA.FromPKCS1.decodeFromTlv(Asn1Element.parse(keyBytes).asSequence())

}

}

object FromPKCS8 : Asn1Decodable<Asn1Sequence, CryptoPrivateKey> {
@Throws(Asn1Exception::class)
override fun doDecode(src: Asn1Sequence): CryptoPrivateKey = runRethrowing {
//PKCS8 here
require(src.nextChild().asPrimitive().decodeToInt() == 0) { "PKCS#8 Private Key VERSION must be 0" }
val algorithmID = src.nextChild().asSequence()
val algIdentifier = ObjectIdentifier.decodeFromTlv(algorithmID.nextChild().asPrimitive())
val algParams = algorithmID.nextChild().asPrimitive()
require(algorithmID.hasMoreChildren() == false) { "Superfluous Algorithm ID data encountered" }
require(!algorithmID.hasMoreChildren()) { "Superfluous Algorithm ID data encountered" }
val privateKeyStructure = src.nextChild().asEncapsulatingOctetString().let {
val seq = it.nextChild().asSequence()
require(it.hasMoreChildren() == false) { "Superfluous private key data encountered" }
require(!it.hasMoreChildren()) { "Superfluous private key data encountered" }
seq
}
val attributes: List<Asn1Element>? =
Expand All @@ -577,10 +566,7 @@ sealed class CryptoPrivateKey(
}
}

/**
* Representation of an encrypted private key structure as per [RFC 5208](https://datatracker.ietf.org/doc/html/rfc5208)
* As of November 2024, We do not ship decryption functionality
*/
/** Representation of an encrypted private key structure as per [RFC 5208](https://datatracker.ietf.org/doc/html/rfc5208) */
class EncryptedPrivateKey(val encryptionAlgorithm: ObjectIdentifier, val encryptedData: ByteArray) :
PemEncodable<Asn1Sequence> {

Expand Down Expand Up @@ -608,13 +594,4 @@ class EncryptedPrivateKey(val encryptionAlgorithm: ObjectIdentifier, val encrypt
}
}
}

/**
* Convenience wrapper to decrypt this private key.
* Actual decryption must happen in [decryptFn], which gets passed [encryptionAlgorithm] an [encryptedData].
* [decryptFn] may throw anything, as it is executed inside a [catching] block.
*/
fun decrypt(decryptFn: (ObjectIdentifier, ByteArray) -> ByteArray): KmmResult<CryptoPrivateKey> = catching {
CryptoPrivateKey.decodeFromDer(decryptFn(encryptionAlgorithm, encryptedData))
}
}

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